Procedural Data Centers

Once again I was thinking about what new type of building to add to 3DWorld's procedural cities. Data centers are probably the most popular (and controversial) building type in 2026, so that was a good candidate to add. Some people love them because they're needed for AI, which is supposedly "the future." Some people hate them due to environmental impacts of their high electricity and water usage. Maybe years from now we'll all find out if they were a good investment. I'm not here to present my opinion on data centers, I'm only here to add them to my procedural world. With that out of the way, let's begin.

Exterior 

Let's start with building selection. I've never visited a data center in person, even though they've existed in some form for a long time. I can tell from the various photos online that they're usually very large, flat, and rectangular. That's convenient for me because simple rectangular buildings are easier to subdivide into rooms anyway. I do want to find buildings that have a large footprint but aren't very tall. Now this is unfortunate, because those types of buildings are already assigned as factories, parking structures, warehouses, and power plants.

Wait, I haven't shown power plants yet. Part of the reason is because they're technically not completed, at least not as completed as data centers currently are. The other reason is that they're very similar to factories. They have the same machines, tanks, ladders, catwalks, tall ceilings, etc. The floorplan is the same. The only major differences are that they have generators in place of conveyor belts and more smoke stacks. I can't be distracted by power plants here. Maybe I'll write a post on them later.

Anyway, back to data centers. The other building types I mentioned are limited to 4 floors tall, so I can at least make the ones that are 5-6 floors and a large enough footprint into data centers. That gives me around 50 of them in my city of ~10K houses and ~5K buildings. These only appear in my secondary city areas since the city centers with their grids of roads almost always have buildings taller than 6 floors. I think it's possible to get a data center in those cities, but so far I haven't seen one.

Data centers have walls using one of several concrete block or brick textures, and windows only around the office sections and ends of the building. I've had the ability to customize window placement per-side and per-floor since adding factories a few posts ago. I removed the windows from the server rooms because they seem unnecessary and block valuable sever space. Plus, they don't alpha blend properly with the interior windows I added. (More on that below.) I also removed the windows from the sides of utility rooms so that I don't have to worry about blocking them with machines and pipes. Fewer windows are more efficient and also make object placement easier - win/win! I did have to add various air intake and exhaust vents where the windows would normally go to break up the empty wall space and make the layout a bit more functional.

I changed the roof type to always be flat so that I can cover the rooftop with cooling goodness. The building exterior geometry generator was already adding skylights to the roofs of some of these buildings. Skylights don't seem to cause any problems since they're over the central hallway, so I left them in. Data centers are massive energy hogs and need a ton of cooling, so I absolutely littered the roof as well as the sides of the buildings with AC units. But those normal office building sized units don't do it for me. They're too small. No, I later went back and added 2-4 of these huge house sized cooling towers on the roof with two circular fans on the top of each one. I couldn't find a suitable free 3D model and instead created them with textured cubes and cylinders. It's a good fit since everything else on the roof is made of simple shapes as well.

I wanted to fill these buildings with pipes and ducts, since I feel oddly satisfied by writing thousands of lines of pipe routing code. It's very time consuming though, which is why I've only added a minimal amount of water, gas, and coolant pipes so far. I made the coolant lines (both outgoing and return) a light blue to get some more colors in an otherwise grayscale building. I did see some reference images with blue pipes on the roof. The system of pipes and ducts is fully connected to everything and extends from the utility inputs in the basement, all the way through the floors to the cooling towers on the building roof. Here's a screenshot of a typical data center rooftop view.

Data center exterior view showing rooftop cooling towers, AC units, skylight, windows, vents, and pipes.

And here's another angle of the roof on a different data center where you can see the end and sides of the building. The back end with the vents and utility rooms is facing the camera, while the other end with the offices is facing away. The smaller AC units along the sides of the building can be for the office spaces and non-server rooms.

Rooftop view of another data center without a skylight. A row of smaller AC units can be seen on the ground along the side of the building.

Here's a smaller data center with only two cooling towers and a brick texture. This one has some right angle turns in the rooftop coolant pipes. Pipe routing is quite difficult because of the way the building is generated in stages: exterior, roof objects, interior floorplan, interior objects. The cooling towers are placed before the building knows where the interior air handlers are! I had to shuffle the machinery around to make everything fit and find a way to route the pipes around obstacles. This took me many hours to get right.

Smaller data center viewed from above. This one has a company sign.

I assigned one data center the name "Skynet" as an Easter egg for the player to find. It happens to be near the edge of my island where the ocean water is visible in the background.

Skynet. Surely you get the reference.

Interior

Now we'll move to data center interiors. These are generally well lit and open spaces, with very little dirt and wear. I've replaced some of the rusty and dirty textures and objects found in industrial buildings with shiny versions to reflect how new these buildings are. I did leave the basement and parking garage dirt though. Maybe the building was something else that got repurposed as a data center? On second thought, I set water and crack damage to zero for data center basements.

The main floorplan is shared across the 5-6 above ground floors and starts with a wide hallway that runs the entire length of the building in the long direction. Sometimes this hallway is centered, and other times it's offset a bit to the side to make an asymmetric interior. This happens when there are an odd number of windows on the short dimension. The wider side of the hallway contains stairs and an elevator together at the end with the front entrance door. I put them both on the side of the hallway rather than the center because someone thought the center stairs looked odd. This uses a different variant of my U-shaped stairs that has an open wall with a window visible in the side. I changed parking structures to use a similar type of stairs shape with the missing wall and window at the back to make it look more open.

Here is what this area of the building looks like. Note that the elevator floor display is now using digital numbers. I made the code used to create digital clocks more general so that it can be used to add 7-segment numbers and letters to other types of building objects.

Interior of a data center showing the stairs and elevator to the side of the main hallway and the door to the operations center on the right.

I'll continue walking down this hallway. The main office area, which I'm referring to as the operations center, is placed next to the elevator. This room typically occupies three windows worth of the building length, though it can only be two windows for short data centers. The room itself is an odd non-rectangular shape because it has the stairs and elevator footprints cut out of it. This is sort of a mix of an office and a conference room that I had to write custom placement logic for. There are rows of desks with office chairs and computers placed along the walls, with a long conference table and chairs in the center of the room. I put a digital clock on one wall and some smaller objects such as filing cabinets and trash cans against walls. Some buildings have a door connecting the operations center to the server room. There's quite a bit of unused space in the larger rooms. I'm still thinking about what else I can place there.

This is what I call the "operations center". It's full of desks with computers and a big conference table with chairs in the center. The elevator wall is just barely visible on the left.

The next room we encounter along the hallway is the server room. There's actually one on each side of the hallway in a symmetric configuration. I thought it would look neat if I added glass windows between the server rooms and the hallway to improve visibility and make the hallway more interesting. Normally glass windows don't alpha (transparency) blend correctly with exterior building windows. But fortunately, there are no windows in these server rooms. That's actually one of the reasons I removed server room windows. I should probably have the server room doors start out as closed and locked, though for now they're sometimes left open.

View of the server room through glass windows in the main hallway.

The interior of the server room is exactly what you would expect: rows of groups of server racks. I started with office building server rooms that had server racks along the walls and added more of them in the center of the room. I combined racks into groups of 8 because that's a convenient power of 2 (8 bits = 1 byte). These groups are repeated in rows and columns with aisles in between, similar to the approach I used to place store shelf racks. Server rooms use a new metal floor tile texture based on what I remember seeing in the server room at the company where I work. I added plenty of vents in both the ceiling and floor for air flow to cool the servers.

I'm not all that happy with the same repeating gray texture used for each rack. I would prefer more variety, though in reality data centers probably do have thousands of exactly the same server rack in rows like this. I did want to avoid any brand names here. The servers along the walls are bit different because they have conduits running from the top of the rack into the ceiling. It was too difficult adding these to the rows of servers in a way that avoided the ceiling lights, so I omitted them for interior rows. We can say the racks along the walls are for networking rather than compute and that's why they have extra cabling. Maybe I'll connect these with wire harnesses at some point in the future when I get back to working on this area of the building. 

Inside the server room itself. Row after row of groups of 8 servers, with plenty of ceiling lights and air vents everywhere.

The other side of the hallway across from the stairs, elevator, and operations center is split into various smaller rooms that differ across floors. There are men's and women's restrooms on the lower two floors. I put a security room with security monitors on the ground floor. The rest are individual offices, a kitchen/break room, and other standard rooms found in office buildings.

 

Utility Rooms

If we keep walking we'll find ourselves at the other end of the hallway, in the back of the data center. This is the opposite side of the server room from the operations center, where the utility room was added to provide power and cooling for the servers. I want to create a whole new blog section for data center utility rooms because I have a lot to say about them. This single room type was probably at least a third of the total effort of creating data centers. It has three new object types as well as a variety of ducts and pipes that took several iterations to get right. It was quite a lot of effort - but I did enjoy working on this part.

The utility room typically accounts for two windows of length of the building, though the side windows themselves aren't drawn. They're not needed and only block the objects and pipes. The floor is bare concrete. Equipment is added in rows starting at the wall shared with the server room and working toward the back wall of the building until there's no space left. I added enough of a gap between rows of equipment for the player and building people to walk.

Placement starts with UPS backup batteries along the server room wall. I used the commercial refrigerator 3D model that I also use for commercial kitchens because it looked like a good battery cabinet to me. It's made of shiny metal with access doors on the front and some lights with digital displays. Surely no one will notice that it's also used as a fridge, right? I added a fan - no, pair of fans - to the top to make it look more like a battery. This is a free 3D model I found when looking for models to add to factories a few months ago. I think it's supposed to be a GPU cooler, but it's good enough for this application. And to finish off the battery, I placed a black power conduit running into the ceiling. Maybe this connects to the row of batteries on the floor above or the conduits at the top of the servers along the walls.

Oh, here I'm assuming that the power connections run through the floors/ceilings to connect everything together. I may go back and add proper power cables across the bottom of the ceiling at some point. I also intend for the ducts providing air flow to the vents in the sever room to run though the ceiling, even though there technically isn't enough space between the ceiling and floor for ducts. I suppose my buildings have too little space for this purpose. However, it's not obvious to the player since the floor/ceiling cross section isn't really visible anywhere.

Next from the server wall are the row of air handlers/heat exchangers for cooling the server racks. These are gray painted metal rectangles with those same GPU fan pairs added to each side. I'm not quite sure what purpose these side fans serve, but they do make these objects look more like air handlers. Maybe thet provide cooling for the utility room itself? Each unit is connected to a large duct at the the top as air intake. These are joined together across all units in the room and meet with a vertical duct at the far side of the room along the exterior wall of the building. This duct runs the entire height of the building and connects the utility room ventilation systems together across stacked floors. There are air intake vents on the side of the building, the roof, and down in the parking garage if one is present. The air exits each air handler through the floor.

Air handlers also have four pipes connected to them: coolant in, coolant out, water in, and waste water out. Coolant pipes are light blue to add some brighter colors. Water pipes are copper with brass fittings and drain pipes are white PVC plastic. I couldn't quite decide if I wanted to make the data center AC system water or air cooled, so I made it a combination of both so that I could add more pipes. I suppose the waste water pipe would be needed as a condenser drain even if there was no water cooling. The water and drain lines run vertically through the floors connecting to each stacked air handler, and are merged together with horizontal pipes in the basement.

Utility room with UPS/batteries, AC air handlers/heat exchangers, power transformers, and backup generators.

In contrast, all coolant pipes merge horizontally across the air handlers in each utility room. This produces a pair of pipes on each side of the air intake duct for each side of the building on each floor. These pipes run vertically up the inside of the exterior wall in a tight group all the way up to the roof where they turn and enter the sides of the cooling towers. Half of these pipes continue through the cooling tower and connect to the second row of cooling towers if there is a second row. Routing these pipes took quite a bit of effort and many attempts to avoid having them intersect each other or anything else in the room. Moving the ceiling lights around to avoid everything was particularly troublesome. Keep in mind that both the rooms and objects themselves are randomly different sizes, with some variations in configurations, so the placement logic has to work with all variants. The screenshot below shows how the coolant pipes are routed.

Close-up of utility room pipes and ducts used for server cooling.

I'm not entirely sure this cooling system is correct for data centers. I originally thought it worked like my house's air conditioner with a single closed loop of refrigerant, an outdoor compressor + fan, and an indoor fan. In that case the rooftop cooling towers would have both the compressor and the exterior fan. Then later I read more about it and it seems like most data centers have two separate closed loop liquid cooling systems with a chiller between them. I didn't initially add the chiller, and now there's no space for it. Maybe it can be inside the cooling tower and not visible? There certainly should be enough space for it in there.

Household AC systems have a narrow high pressure refrigerant line and a larger width lower pressure line. I made both of my coolant lines the same radius because that's what I saw in most of the diagrams and reference images I found online. I also found it odd that these don't appear to be insulated to reduce heat transfer with the surrounding air. Maybe the pipes in my reference image are in fact insulated with a thinner metal pipe at the core?

The next row of equipment consists of step down power transformers that convert higher power line voltages to the lower voltages used by individual server racks. They also power the coolant compressors and all of the various fans. I used the same substation model that I have next to office buildings along city streets and in factories, power plants, and office building utility rooms. These transformers already have power conduits running downward into the floor.

The forth and final row consists of a line of generators that provide backup power when needed. I found a nice 3D model of what I believe is a diesel generator online. I added these generator models to power plants and some of the underground extended basement machine rooms as well. There's a part on the top that looks like it could be an exhaust vent, so I connected a duct to this point. The duct makes a right angle turn, runs along the ceiling, and exits to a vent on the back wall of the building above the window. That's probably good enough, considering the generators are only meant to run for short times during power outages.

I added a fuel line connecting to the side of each generator. I used a yellow color to get a good contrast with the blue generator color and blue cooling pipes. I know this is supposed to be a diesel generator and yellow is usually used for natural gas pipes, but I don't care. These fuel lines run vertically through each floor to connect the stack of generators, and are connected together horizontally in the basement just like the water pipes. This works because the equipment layout is the same for utility rooms on each floor. The utility rooms on each side of the hallway can be slightly different though.

Utility room viewed from the side with the generator models.

Sometimes there's extra space for the player to walk between the generators and the back wall, and other times there isn't. I added space between adjacent generators for the player to walk instead. Some shorter length utility rooms don't have enough space to place generators in the long dimension, so I add them sideways. The exhaust vents and pipes are adjusted for this orientation. I have a screenshot of this configuration shown below.

Utility room with lengthwise generator placement. Only 4 generators will fit.

Occasionally the utility room is so short that generators don't even fit when rotated. In this situation, I split the third row into two roughly equal sections of transformers and generators. Generator orientation is selected to get the best fit and pack them as tightly as possible within the available space. Here's an example of a mixed transformer/generator row.

Utility room with split generators and transformers in the third row.

This is as far as I've gotten before my summer trip. I'll most likely go back and work on some of these data center areas before my next blog post. Writing all of this up gives me new ideas, and sometimes I even get useful feedback and suggestions from others who read my posts.

I suppose I need to add this in today's world:

Disclaimer: No AI/LLM was used for this work except for minor line completion with GitHub Copilot in Visual Studio, which doesn't understand the 3D code very well and isn't very helpful.